The present invention pertains to a process for printing substrates and substrates printed thereby, and more particularly to a folded substrate, dual-sided printing process and substrates printed thereby.
Printing of fabrics with various patterns and colors is well known. Some of these fabrics are used to make wearing apparel, window curtains, furniture coverings, luggage covers, and the like. Since these fabrics will experience the multiple rigors of heavy use, staining, washing, or the like, they are made of relatively sturdy and durable material that will not substantially wear out over an extended period of time.
Fortunately for the ink printing of these sturdy, durable fabrics, their relative thickness and/or density benefits the printing process used to print colored patterns, or the like, on the fabrics. In particular, the problem of ink strikethrough, i.e., printed ink running through the fabric, is absent, since the ink printed on these fabrics is absorbed within the very thickness of the fabric itself.
However, when it comes to printing lower basis weight, i.e., less thick and/or less dense, fabrics, significant problems begin to arise. Because low basis weight fabrics are relatively thin, and inherently include a large number of small voids, or a smaller number of larger voids, any ink or inks printed thereon will run through, i.e., strikethrough, the fabric. The problem with ink strikethrough is that the ink builds up on, for example, an impression cylinder of the printing apparatus. This ink buildup on the impression cylinder results in poor print quality on the fabric, the transfer of ink to the back of the fabric, and poor operating efficiency due to machinery down time required to remove the ink buildup.
This problem becomes even more significant in high speed printing environments, where ink buildup is accelerated and increases the number of times the machinery needs to be shut down for removal of the buildup. As shut down times increase, so do waste of material and ink that are associated with machinery start-up.
One attempt to resolve the problem of ink buildup is the use of doctor blades on an impression roll or the like. Although doctor blades remove ink buildup while machinery is operating, their use prematurely wears out the surface of the cylinder or roll supporting the fabric. This, in turn, results in increased costs due to replacing prematurely worn out equipment.
Another attempt to eliminate ink buildup is the running of an extra layer of material between the fabric and print rollers. The layer is designed to collect or absorb ink strikethrough and carry it away. This has proved to be costly since either the layer must be replaced with a new layer, or the layer must be cleaned of the ink before being rerun through the printing apparatus.